32-bit MCUs boost in-vehicle security and tamper-proof ECUs

Infineon Technologies has introduced 32-bit microcontrollers its AUDO MAX family that incorporate integrated security hardware. The new AUDO MAX SHE (Secure Hardware Extension) microcontrollers extend the tamper-proofing of electronic control units (ECU) and protect against tuning, for example. AUDO MAX SHE enables automotive manufacturers to ensure the integrity of their ECUs and to better guard against exposure to liability claims. Three of the AUDO MAX family now come with SHE functionality.

With the debut of AUDO MAX SHE, the company is claiming a head start over other semiconductor manufacturers in meeting improved tamper-proofing and anti-theft protection of automotive control units as noted by the HIS (Manufacturers’ Software Initiative) Working Group on security. Members of this working group are Audi, BMW, Daimler, Porsche and Volkswagen.

As background, security solutions have so far been confined to software level or were coupled with additional external hardware, meaning they were easily circumvented. Infineon now offers more than this software protection because AUDO MAX SHE monolithically integrates a secure keystore which cannot be read without access authorization. Infineon’s integrated approach claims advantage over the version using external security chips in that the communication does not run via interceptable external bus systems.

In addition, SHE has a cryptographic module which encrypts access codes with up to 128 bits. SHE is complemented by an array of hardware functions which, for example, prevent the application code from being illegitimately read and altered, or identify ECUs in the system network. These are important functions for tamper-proofing control units and protecting them against theft, says the company. Even if such an ECU were to be fitted in another identical vehicle, its engine performance characteristics could not be changed: The cryptographic individual key of an ECU has to match all the cryptographic keys within the ECU network of a vehicle. And that key is safely stored in the SHE.

Infineon says AUDO MAX SHE brings security from the software level to the hardware. Thus, for example, the keystore cannot be read by the diagnostic software and therefore the secret keys are protected from software attacks. Furthermore, AUDO MAX SHE guards against any tampering even during boot-up: The secure boot feature ensures that only the original software is loaded during the boot process.

“Our AUDO MAX is a 32-bit microcontroller for powertrain and chassis applications providing very high performance and real-time capabilities,” said Peter Schaefer, VP and general manager, microcontrollers, Automotive Division of Infineon. “By incorporating SHE, the AUDO MAX microcontroller provides security in every respect: Functional reliability, data integrity, and tamper-proofing.”

AvailabilityThe AUDO MAX microcontroller family incorporating SHE currently comprises three products, each with 4 MB flash memory but differing in terms of clock frequency and package: TC1798 (300MHz, BGA-516), TC1793 (270MHz, BGA-416) and TC1791 (240MHz, BGA-292). All are available in sample quantities. Volume production has begun for the TC1793 and is set to begin for the TC1798 and TC1791 from Q1/2012. Infineon’s future 65 nm eFlash microcontrollers will offer and significantly extend the SHE functionality with a Hardware Security Module (HSM).